The present invention relates to data communications.
In data communications arrangements, such as voiceband multipoint networks, the so-called user data transmitted from one modem to another is preceded by a header which contains signals, or information, used by the modems themselves, herein referred to as "modem-to-modem data". The modem-to-modem data in the header may include, for example, (a) an address or other identification of the transmitting modem used in multipoint applications for so-called coefficient "jam setting" or to maintain various diagnostic parameters on a per-tributary-modem basis, (b) a sequence number such as taught in my co-pending U.S. patent application, serial number 137,995 entitled "Measurement of Missed Start-Up Rate and Missed Message Rate," assigned to the assignee hereof and filed of even data herewith, and/or (c) a checksum used in the receiver to determine whether the address, sequence number or other header data was correctly recovered.